What is a Daubert challenge? It is a legal motion that asks a judge to block expert testimony from being used at trial. In mass tort cases, this matters a great deal. Companies often use Daubert challenges to try to exclude scientific experts who link their products to injuries. If the challenge succeeds, the entire case can fall apart.
The name comes from a 1993 Supreme Court case called Daubert v. Merrell Dow Pharmaceuticals. That ruling changed how federal courts evaluate expert evidence. Understanding what is a Daubert challenge can help you follow your own mass tort case more clearly.
How What Is a Daubert Challenge Works in Federal Court
To understand what is a Daubert challenge, you need to know about Federal Rule of Evidence 702. This rule says expert testimony is only allowed if it is based on reliable methods and relevant facts. The trial judge acts as a “gatekeeper.” Before a jury ever hears from an expert, the judge must decide if that expert’s methods are trustworthy. Either side can file a Daubert motion asking the judge to exclude the other side’s expert.
The judge typically holds a special hearing called a Daubert hearing. During this hearing, the judge examines the expert’s methods using several factors. Can the theory be tested? Has it been peer-reviewed and published? What is the known error rate? Is the method generally accepted in the scientific community? The judge does not decide who is right about the science. The judge only decides whether the expert followed sound methods to reach their conclusions.
In mass tort litigation, what is a Daubert challenge usually looks like this: the defendant files a motion to exclude the plaintiff’s causation experts. Causation experts are the scientists who testify that a product caused harm. These hearings often happen early in multidistrict litigation (MDL) cases. A single ruling can affect thousands of claims at once. That is why Daubert challenges carry such high stakes in mass tort cases.
Why What Is a Daubert Challenge Matters for Your Case
If you are part of a mass tort lawsuit, what is a Daubert challenge could determine your case’s future. Plaintiffs must prove that a product caused their injury. They do this through expert witnesses. If a judge excludes those experts, there may be no way to prove causation. Without causation, the case cannot move forward. The defendant can then ask for summary judgment, which dismisses the case entirely.
The risk is not equal for both sides. Defendants only need to knock out general causation experts once. That single ruling can end an entire MDL involving tens of thousands of claims. Plaintiffs, on the other hand, must successfully defend every expert. Research shows that 40 to 50 percent of Daubert motions result in full or partial expert exclusion. A RAND Institute study found that after the Daubert standard took effect, successful summary judgment motions roughly doubled. About 90 percent of those went against plaintiffs.
In December 2023, an important update took effect. The amended Federal Rule of Evidence 702 now states clearly that experts must meet their burden “by a preponderance of the evidence.” This means courts should apply a stricter standard when evaluating experts. For mass tort claimants, this makes understanding what is a Daubert challenge even more important. You should consult a licensed attorney to understand how this change may affect your specific case.
Real-World Examples of Daubert Challenges in Mass Tort Cases
The Zantac MDL is one of the most dramatic examples of what is a Daubert challenge in action. In December 2022, a federal judge in Florida excluded all ten of the plaintiffs’ general causation experts. The judge found their methods unreliable. That single ruling effectively ended more than 50,000 federal cases. The Delaware Supreme Court later reversed a state-court ruling that had allowed plaintiffs’ experts, eliminating roughly 75,000 additional state claims.
The Tylenol (acetaminophen) MDL offers another clear example. In December 2023, a New York federal judge excluded all five of the plaintiffs’ causation experts. This was one of the first major rulings to cite the newly amended Rule 702. The court found the experts failed to reliably apply accepted scientific criteria. By August 2024, the court granted summary judgment and dismissed all pending MDL cases. Families who believed acetaminophen caused autism or ADHD in their children lost their path to trial.
| MDL Case | Daubert Outcome | Impact |
|---|---|---|
| Zantac (ranitidine) | All 10 plaintiff experts excluded (Dec. 2022) | 50,000+ federal cases effectively dismissed |
| Tylenol (acetaminophen) | All 5 plaintiff experts excluded (Dec. 2023) | All pending MDL cases dismissed by Aug. 2024 |
| Roundup (glyphosate) | Plaintiff causation experts upheld | Cases proceeded to trial; settlement negotiations ongoing |
| Talcum Powder (J&J) | Daubert motions pending as of 2025 | ~90,000 ovarian cancer claims await ruling |
| AFFF/PFAS (firefighting foam) | Daubert briefing concluded mid-2025 | Bellwether trials scheduled for late 2025 |
The Roundup MDL shows the other side. There, the court largely upheld the plaintiffs’ experts. That allowed cases to reach juries, which led to significant verdicts. The contrast between Roundup and Zantac shows how much what is a Daubert challenge can change the outcome of mass tort litigation.
Common Misconceptions About Daubert Challenges
Many people misunderstand what is a Daubert challenge. The biggest myth is that the judge decides who is scientifically correct. That is not the case. The judge only evaluates whether the expert used reliable methods. Two experts can disagree, and both may pass a Daubert challenge. The question is methodology, not conclusions. If an expert followed accepted scientific steps, the jury gets to hear them.
Another misconception is that a Daubert challenge only applies to scientific testimony. That was true in 1993. But the Supreme Court expanded the rule in 1999 with Kumho Tire Co. v. Carmichael. Now what is a Daubert challenge applies to all expert testimony. This includes engineers, economists, medical doctors, and financial analysts. Any expert witness can face a Daubert motion.
Some claimants also believe that if their expert is excluded, they can simply find a new one. In an MDL, it rarely works that way. Daubert rulings on general causation apply to all cases in the MDL. The court evaluates the best experts the plaintiffs can find. If those experts fail the Daubert test, replacement experts are unlikely to fare better. That is why these early hearings are so critical.
📨 Get Free Mass Tort Guides Alerts
Free · No spam · Unsubscribe anytime
What This Means for You
If you are involved in a mass tort case, what is a Daubert challenge is something you should discuss with your attorney. Ask your lawyer about the status of Daubert motions in your MDL. Find out whether the court has scheduled a Daubert hearing. Learn which experts have been retained and what methods they plan to use. This information can help you understand the strength of your case.
You should also know that what is a Daubert challenge does not apply the same way in every state. Federal courts and most state courts follow the Daubert standard. But some states still use the older Frye standard, which only looks at general acceptance. Your attorney can explain which standard applies to your case. The standard used can significantly affect your chances of presenting expert evidence at trial.
Finally, be patient. Daubert hearings in large MDLs can take months or even years to resolve. The talcum powder MDL has roughly 90,000 claims waiting on Daubert rulings. The AFFF firefighting foam litigation involves complex science on multiple cancer types. These are not quick decisions. But they are among the most important steps in any mass tort case. A licensed attorney can help you understand what is a Daubert challenge and how it may affect your potential compensation.
Frequently Asked Questions
What is a Daubert challenge, and who can file one?
A Daubert challenge is a motion asking a judge to exclude expert testimony. Either side can file one. In mass tort cases, defendants most often file Daubert motions to challenge the plaintiffs’ scientific experts. The judge then holds a hearing to evaluate whether the expert’s methods are reliable under Federal Rule of Evidence 702.
How long does a Daubert challenge take to resolve?
It depends on the complexity of the case. In a single lawsuit, a Daubert hearing might take weeks to a few months. In a large MDL with thousands of claims, the process can take a year or longer. Both sides submit extensive briefing and expert reports before the hearing. The judge may take additional months to issue a written ruling.
Can a mass tort case survive if a Daubert challenge succeeds?
It is very difficult. If a judge excludes all general causation experts, plaintiffs typically cannot prove their case. The defendant will then seek summary judgment. However, rulings can be appealed. State court cases may also continue under different evidentiary standards. You should consult a licensed attorney to understand the specific impact on your claim.
Check If You May Qualify
Mass tort eligibility depends on your specific exposure, injuries, and the state where you live. A licensed mass tort attorney can evaluate your situation at no upfront cost — most work on contingency, meaning you pay nothing unless you recover compensation.
Official Sources & Resources
For verified mass tort and MDL information:
- JPML: jpml.uscourts.gov — official MDL statistics and transfer orders
- DOJ: justice.gov — settlement announcements and press releases
- FDA: fda.gov — drug recalls, warning letters, and safety alerts
- CDC: cdc.gov — health condition data and exposure guidelines
- EPA: epa.gov — environmental contamination data
- Cornell LII: law.cornell.edu — plain-English legal definitions
Content last reviewed May 2026. This is general educational information, not legal advice. If you notice outdated information, please contact us.
Related Guides
- All Active MDL Cases
- More in This Category
- Tort Reform by State — 50-State Comparison
- All 50 State Tort Reform Guides
- Mass Tort Explainers
- Demographic Guides
- Mass Tort Tips
- New Jersey Tort Reform Guide
- Ohio Tort Reform Guide
- Illinois Tort Reform Guide
Attorney Advertising. The information on this page is provided for general informational purposes only and does not constitute legal advice. No attorney-client relationship is created by accessing or using this content. Every case is unique, and results depend on the specific facts and circumstances involved. Past settlement amounts and case outcomes do not guarantee similar results in your case. If you believe you have a legal claim, you should consult with a licensed attorney in your jurisdiction who can evaluate your specific situation.